Multiple electric outlet



May 14, 1957 A. COHEN 2,792,561

MULTIPLE ELECTRIC OUTLET I5 Sheets-Sheet 1 Filed Dec. 8, 1955 IN VEN TOR.

ALEX COHEN May 14, 1957 A, COHEN 2,792,561

MULTIPLE ELECTRIC OUTLET 3 Sheets-Sheet 2 Filed Dec. 8, 1955 .2 .EZg../.Z.v INVENTOR.

ALEX COHEN @IM IIIHIII May 14, 1957 A, COHEN 2,792,561

MULTIPLE ELECTRIC OUTLET 3 Sheets-Sheet 3 Filed Dec. 8, 1955 INVENTOR.

E- j B ALEX COHEN 2,792,561 MULTIPLE ELECTRIC OUTLET Alex Cohen, Rego Park, N. Y. Appiication December 8, 1955, Serial No. 551,8i1 5 Claims. (Cl. 339-157) This invention relates to electrical outlets, and more particularly has reference to an attachment to a conventional duplex, wall or licor-mounted receptacle. Summarizecl briefly, the invention comprises a casing having spaced, prongreceiving slots or sockets in a plurality of walls thereof, so as to permit attachment thereto of a substantial number of electric plugs of the two-prong type, such as are provided upon the ends of lamp or appliance cords. Projecting forwardly from one wall of the casing are spaced pairs of prongs or tongues, each of said pairs of prongs being adapted for engagement in one of the pairs of prong-receiving slots of the duplex receptacle. rthis provides a four point anchor for the device in the associated, conventional receptacle, and to further insure the iirm and rigid attachment of the device to ysaid receptficle, there is provided an elongated anchoring or connecting screw, extendable directly through the casing and engageable in the usual, centrally disposed aperture provided in the face plate of the receptacle for threading into the receptacle body in back of the face plate in place of the usual small connecting screws generally connecting the face plate to said body.

Within the casing, there is provided a plurality of plural contact elements, so designed that on insertion of the prongs of an electric plug in any selected pair of slots of the casing, electrical power will be supplied through the receptacle to the appliance from which the cord, carrying said plug, extends.

it is not broadly new to provide multiple electric outlet attachments for receptacles. Heretofore, however, a completely rigid connection of the attachment to the receptacle, achieved in the present instance by the four, rectangularly spaced prongs of the instant invention and by the elongated anchoring screw, has not, so far as is known, been provided. Accordingly, one important object of the present invention is to provide a generally irnproved electrical outlet attachment for duplex receptacles, that will permit the device to be swiftly and easily connected to the receptacle, while yet insuring a fully rigid connection of the device to the receptacle.

This is of importance, it may be noted, in view of the fact that heretofore, multiple outlets, under the weight and pull of the cords extending therefrom, have generally tended to become loose within the receptacle, and in many instances, have been pulled by the cords completely out of the receptacle. In other instances, the partial, accidental withdrawal of the multiple electric outlet attachment from the associated receptacle has exposed portions of the conductive prongs of the outlet attachment. This, of course, presents a serious hazard to children as well as adults, by unnecessarily exposing them to electric shocks should they come in contact with the exposed parts of the outlet prongs.

Further, in many instances the generally analogous devices of the prior art have been unnecessarily complex, as a result of which they can be manufactured only at a cost so high as to render the same unsuitable for corn- Jnercial production. In this particular art, it may be nited AStates Patent O iit) 2,792,561 Patented May 14, 1957 ice noted, a highly competitive situation exists, requiring that production costs be cut to a complete minimum if a particular device is to be commercially feasible. Another important object of the invention, accordingly, is to provide a relatively simpliiied construction, considering the benefits to be obtained from the use of the device, which construction, while permitting a substantial number of electric plugs to be connected to the device, and while also insuring that the device will be rigidly attached to the receptacle without possibility of accidental withdrawal even to a slight degree, will be capable of manufacture at a comparatively low expense.

A further object of importance is to provide a multiple electric outlet as described that will include a novel assembly and interrelationship of a pair of complementary casing sections, and a plurality of contact plates each of which has prong-engaging tongues struclc out of the material thereof, said tongues being registrable with the prongreceiving slots of the device responsive to insertion of the plates in and between the respective casing sections and connection of the casing sections to each other.

Still another object, in at least one form of the inventionii, is to provide a multiple outlet of the type referred to wherein a center screw will be used for anchoring the device to a conventional wall or door-mounted receptacle and will be threadable into a centrally disposed recess of said receptacle in substitution for the usual face plate attaching screw provided therein. It is proposed that said screw constitute an internal ground connection for a conventional triple electric plug of the type having a pair of prongs through which current may flow from and back to the receptacle for energizating an electrical appliance associated with the plug, and having also a ground prong.

For 'further comprehension of the invention, and of the objects and advantages thereof, reference will be had to the following description and accompanying drawings, and to the appended claims in which the various novel features of the invention are more particularly set forth.

ln the accompanying drawings forming a material part of this disclosure:

Fig. l is an exploded perspective view showing a conventional duplex receptacle, and a multiple outlet attachment formed in accordance with the present invention.

Fig. 2 is an end elevational view of the outlet as it appears when attached to the receptacle, a plurality of electric plugs being engaged with the outlet.

Fig. 3 is a longitudinal sectional view through the outlet on line 3-3 oi Fig. 2.

Fig. 4 is a longitudinal sectional view on line 4 4 of Fig. 3.

5 is a perspective View of the inner or front casing section per se.

6 is a perspective View ot the outer or rear casing section per se.

Fig. 7 is a perspective view of the contact plate assembly per se.

Fig. 8 is a side elevational view of one of the outer contact plates.

Fig. 9 is an edge elevational View of said outer contact plate, as seen from the line 9-9 of Fig. 8.

Fig. l0 is a side elevational view of one of the inner contact plates.

Fig. ll is an edge elevational view of the inner contact plate as seen from the line ll-ll of Fig. l0.

Fig. i2 is a view similar to Fig. 2 but illustrating a modified torni of the invention.

Fig. 13 is a perspective, partially exploded view of the modiied outlet shown in Fig. l2.

Fig. is a fragmentary perspective view of the contact plate assembly of the modified form.

Fig. l5 is an enlarged perspective view ot". the ground contact element of the modified form, per se.

Fig. 17 is a fragmentary'perspective view of the outer or rear casing section o f the modiiied construction.

Fig.Y `i8 isa fragmentary view in elevation of the front vcasing-section of the modified construction, with the contact plates and ground element mounted therein.

Referring to the drawings in detail, the reference numeral it) generally designates a conventional duplex receptacle, mounted in a wall W. In this connection, a receptacle of this type is sometimes mounted directly in the floor, and in other instances, the receptacle instead of being extended horizontally as in Fig. l, is extended vertically within the wall. tachment i2 constituting the present invention is adapted for engagement with said receptacle regardless of the particularlocation or position of the receptacle.

As shown in Fig. 2, tre device l?. is adapted to be plugged into the receptacle lil, after which a plurality of Yconventional electric plugs i4, from which extend cords Y16, are engageable in the outlet. The plugs, as usual, are each equipped with a pair of prongs i3 (see Fig. 3) engageable in the outlet in such a manner as to cause an electrical connection to be made between the plugs and receptacle, for the purpose of supplying electric power Vto a lamp or other appliance, not shown, to which the Vcord i6 or" the plug extends.

VAs shown in Fig. l, the receptacle it? includes the usual spaced sockets each having a pair of prong slots 2d, which under normal circumstances receive the prongs i8 of the plugs. Further, the receptacle includes the usual face plate 22 apertured for extension of prong sockets therethrough, and having a centrally disposed opening 24 ordinarily receiving a relatively short connecting screw whereby the face plate is connected directly to the body or casing of the receptacle lll. In accordance with the present invention said short connection screw is removed, to permit threading of an elongated anchoring screw directly into the threaded recess generally provided in the receptacle l0.

assembly generally designated at 30.

Front and rear casing sections are both formed of electrically insulative material, such as a hollow plastic, and vconsidering tirst the construction or" the front casing section, this includes a rectangular front wall 32 adapted to engage against the face plate when the electrical outlet is attached to the receptacle. integral with the front wall at opposite ends thereof are end walls 34, and also integral with the front wall, as well as with the end walls, are side walls 36, 38.

To facilitate a better understanding of the invention, the side wall 36 will hereinafter be termed a top wall, wall 3S will be termed a bottom wall. However, 1t will be understood that these terms are used only in refpositions in which the walls are disposed in the illustrated embodiment of the invention, and of course, if the duplex receptacle is extended vertically in the wall W, the side walls 36, 33 would not be disposed at top and bottom, respectively, of the device, but rather, would extend vertically at opposite sides thereof.

ln the top wall 36 of the casing section 26, there is formed a plurality of slots dit. ln the illustrated example, four of these are shown, but the number could be increased if additional plug-receiving means is desired. In any event, there are two pairs of slots 40, said pairs In the bottom wall 3S, there are formed similarly arranged slots 42, the respective slots 42 being aligned vertically with the slots 40.

the inner or front casing section of the modied construction.

The multiple electric element at- A longitudinally extending partition 4d is disposed medially between the top and bottom walls, in parallelism therewith, and is integral with the front wall as well as with the end walls 34. The partition 44, medially between its ends, has a cylindrically shaped enlargement ad extending transversely thereof, and formed in said enlargement is a smooth-walled bore 4S opening through the front walls 32.

The partition 44 is slotted, through its full transverse dimension, at locations spaced along the length thereof, to provide outer contact-plate-receiving slots Sti and inner contact-plate-receiving slots 52, this arrangement being provided so as to insure the iirrn, immovable retention or" the contact plate assembly 3 0 within the casing.

At its several corners, the casing section has transversely extending, thickened corner portions 54 formed with threaded recess 56 terminating at their inner ends short of the front wall 32.

Referring now to Fig. 3, in the front wall 32, adjacent 'the opposite ends thereof, there are formed horizontally extending, elongated apertures 58, disposed above the partition 44. Below the partition 4d, there are formed in the front wall 32 correspondingly elongated apertures 6@ The back or outer casing section 23, so far as its outer configuration is concerned, is generally similar to the inner casing section. The outer section, thus, has a rectangular back wall 62, top and bottom walls 6d, d6, respectively, and end walls 68. Formed in the top wall 64 are longitudinally spaced slots 76, while in the bottom wall 66 there are formed correspondingly spaced slots 72 opening upon the outer longitudinal edges of the top and bottom walls.

When the casing sections are connected in the manner shown in Fig. l, Vslots 40 and 7d are registered, to provide 'top prong slots in the device. Slots 42, 72 are similarly registered to provide spaced pairs of bottom prong slots.

In the several corners of the outer casing section, there are formed enlargements 74, having smooth-walled openings 75 opening upon the inner and outer surfaces of the outer casing section.

Formed integrally with the end walls 58, medi-ally between the top and bottom walls 64, 66 are partitions 7S, while medially between the opposite ends of the outer casing section, there is formed a partition member titl, having a cylindrical enlargement 82 formed with a smooth-walled bore 84. Adjacent partitions 7S and partition member 80, there are formed rear prong slots Se, said slots being arranged in pairs similarly to the top and bottom pairs of prong slots of the device. As will be noted from Fig. 6, the member Si) is spaced a substantial distance from the members 7S, with the prong slots S6 being disposed adjacent opposite sides of the wide spaces defined between partitions 78, 8i? by this arrangement.

The partition members 78, of the outer casing casing section.

` Designated at 88 are corner connecting screws 38, that are used to connect the respective casing sections to one The screws 88 are adapted to be extended through the openings 76 from the back of the device, and are threaded in the thus to xedly but separably connect the casing sections to each other. ln addition, there is provided a main said screw being of elongated formation as shown in Fig. 1 and being extendable through the registering bores 84, 48 of the respective casing sections, for threaded engagement at its inner end in the usual threaded recess-provided in receptacle 10 in back of opening 24 of the face plate 22.

, Considering now the contact plate assembly 30, this comprises in the present instance four rectangular contact plates of electrically conductive metal, adapted to extend transversely across the casing with the peripheries of the several plates being in engagement with the top, bottom, inner, and outer walls of the casing. The four plates include a pair of outer plates 92 and a pair of inner plates 94. As shown in Fig. 7, struck out of the material of the outer plates 92 are compoundly curved spring tongues 96, offset slightly out of the planes of the plates, while struck out of the material of the inner contact plates are spring tongues 98 of similar formation. Tongues 96, 9S are disposed at the top portions of the plates.

At the bottom portions of the plates, there are provided struclr-out tongues 100, 102 of the plates 92, 94, respectively, and at the back parts of the plates, that is, the parts bearing against the back wall 62 of the outer casing section, there are provided struck-out tongues 104, Sitte of plates 92, 94, respectively. The tongues, it may be noted, are preferably slightly narrower than the prongs i8 of an inserted electric plug, to insure the proper movement of the prongs 1S of the inserted prong between the body part of the plates 92, 94 and the selected spring tongues thereof, as shown in Fig. 3.

Each outer plate 92 is paired with an inner plate 94, with the pairs of the plates being faced longitudinally of the casing as shown in Figs. 3 and 4.

integrally formed upon the front edges of the outer plates 92 are laterally projecting arms 108, and integrally provided upon the free ends of the arms 108 are forwardly projected main prongs 110 adapted for engagement in the slots 20. As will be noted from Fig. 8, the prongs 110 are disposed adjacent the upper edges of the plates 92, thus to engage the upper ones of the slots 20.

The plates 94 are formed, adjacent their lower edges, with laterally projected arms 112 integral at their free ends with forwardly projecting, lower main prongs 114 engaging in the lower slots 20. i

In assembly of the device, the several contact plates are iirst inserted in the slots 50, 52, with the outer plates 92 engaging in slots Si! and the inner plates 94 engaging in slots 52. As will be noted, each plate of a pair has its tongues projected inwardly toward the other plate of the same pair, this construction also being apparent in Fig. 3.

After the plates 92, 94 have been inserted in the manner described, the outer casing section is applied, and the plates 92, 94 will bear against the partition members 7S, 80. The connecting screws 88 are now used to connect the casing sections together, and this will hold the casing sections assembled with each other and with the contact plate assembly, the several contact plates being firmly held against movement within the casing section. The several spring tongues of the contact plates are disposed adjacent the prong slots at top, bottom, and back of the assembled casing.

The device is now ready for attachment to the receptacle, and it is merely necessary that it be positioned against the face plate, after which the anchoring screw 90, substituted for the usual faceplate-attaching screw of the receptacle, is inserted through bores 84, 48 and threadedly engaged in the receptacle.

it will be seen that this provides a fixed anchoring of the device to the associated receptacle, not only by reason of the four, rectangularly spaced prongs 110, 114, which firmly engage in the slots 20 of the duplex receptacle, but also by reason of the use of the anchoring screw. 1t may be noted that some receptacles are so designed that the face-plate-attaching screw is a ground connection, for an appliance such as an electric drill. Appliances of this type are increasingly manufactured with ground plugs or loop-like terminals engageable under the heads of the face plate attaching screws, and when a multiple electric outlet of the type illustrated and described therein is attached to the receptacle, the ground connection of the appliance can still be used to advantage, engaging under the head of the elongated anchoring screw 90.

The device is now ready for use, and in the illustrated embodiment, six diterent electric plugs 14 can be attached thereto. The prongs of the plugs are merely inserted in the selected pair of slots of the top, bottom, or back wall of the device and when the prongs 18 of the plug are inserted, they move between the corresponding top, bottom or back spring tongues and the body portions of the plate from which said tongues are struck, thus springing the tongues outwardly to a slight extent, as shown in Fig. 3, to provide a firm engagement of the plug with the device.

lt is important to note, in this regard, that each contact plate provides plural contacts, by use of the three ditterent spring tongues formed thereon, with one pole or side of thereceptacle. Thus, when a plug 14 is inserted in any selected pair of slots of the casing, one prong thereof will engage a plate 92 and the other will engage a plate 94. Each plate 92 has a main prong 110 extendinginto one slot 29 of the receptacle, while each plate 94 has a lower main prong 114 extending into an opposed slot of the receptacle, thus causing current to ow through one of the contact plates to the appliance by way of one side of the electric plug of the appliance, and to return to the receptacle through the other contacting plate, engaged with the other side of the plug.

ln Figs. 12-18, there is shown a modified construction, wherein the multiple outlet is adapted to receive a triple plug having contact prongs and a grounding prong. ln this form of the invention, the construction is generally similar to the lirst form except tor the provision of means whereby the centrally disposed anchoring screw holds in place a ground contact element disposed interiorly of the casing, in position for engagement by the inserted grounding prong of a triple plug.

The device in this form has been generally designated at ma, and includes inner and outer casing sections 26, 28a, respectively. These are generally similar to the corresponding sections of the first forni, except that the inner casing section, as shown in Fig. 16, is molded with an upstanding abutment 116, adjacent one end of the inner casing section. Abutment 116 projects upwardly rom the longitudinally and centrally disposed rib 448b of the inner section, said abutment projecting outwardly, that is rearwardly, from the open rear side of the inner casing section. The inner casing section has a centrally disposed enlargement 46a, similar to the enlargement 46 of the first form, except that there is integrally formed upon enlargement 46a an upwardly projecting abutment 11S, terminating just below the top wall of the inner casing section.

In this form of the invention, there is utilized a pair of contact plates 92, 94 to be disposed at the left-hand end of the inner casing section, viewing the same as in Fig. 16. At the other end of the inner casing section, however, instead of a second pair of plates 92, 94, there is provided a pair of contact plates 92a, 94a. These are similar to the plates 92, 94, except that the rear tongues 104e, 196e are oppositely twisted obliquely to the planes of their associated plates as shown in Fig. 14.

Oppositely inclined correspondingly to the tongues '1042, M16ZL are back prong-receiving slots 86a of the outer casing section 2Sa (see Fig. 13).

Of course, any set of tongues can be twisted in the manner shown in Fig. 14, that is, the tongues at the upper edges of the contact plates might be so twisted, the tongues at the lower edges, or all the tongues of the plates. Such would be a matter of choice, it being mainly important, for the purpose ot' the present invention, that at least one set include tongues oppositely twisted for purposes to be made more clearly apparent hereinafter.

A ground contact element 120 has been shown in Fig. l5, and comprises a single piece of electrically conductive -Y vice comprising:

-metal material having a vertically disposed attaching Larm formed at itsflower end with an opening 122 receiving the anchoring screw 90a. At its upper end, the farmY merges into a rearwardly oiset contact arm 124 projecting laterally from the attaching arm within the Youter casing section 28a. At its free end, the contact arm 124 has an inwardly turned extension 126 adapted to be engaged by the inserted grounding prong of a triple plug, not shown. Said grounding prong would be inserted through a vertical slot 128 (see Fig. 13) formed in the outer casing section above and between the inclined slots 86a. This is the general arrangement of the prongs of -a triple plug, and it will be seen that when the prongs of such a plug are inserted through the slots 86a, 123, the -current or contact prongs will engage the tongues 1045, 106?, `while the ground prong will engage the contact 'arm 124. The contact arm 124 is electrically connected, -of course, to the anchoring screw 90a by extension of said screw through the opening 122.

As shown in Fig. 17, the outer casing section 28a has a partition member Stia formed with a cylindrical enlargement 82 having a smooth-walled bore 84a. Bore S4@ is larger in diameter than the bore through the enlargement ia, because the head of the screw 90a is to `extend through the bore 34a when the screw is being threaded into the receptacle (see Fig. 12).

The enlargement 82a, as shown in Fig. 17, has its inner end disposed inwardly from the outer surfaces of the adjacent portions of the partition member 80a, as compared to the corresponding component of the rst form of the invention wherein the face of the enlargement is iiush with that of the remaining portion of the partition member 80. This is for the purpose of permitting insertion of the lower end of the attaching arm of the contact element 120 between the enlargements 46a, 82a, respectively.

With the contact element so positioned, the laterally projected arm 124 thereof projects transversely of the plane of the contact plate 94a, and completely clears said contact plate 94a out of contact therewith, due to the provision of a clearance resulting from obliquely cutting n away the upper rear corner of contact plate 94a as at 130. The extension 126 is disposed between the plates 92a, 94a and the vertical arm -20 is supported irmly against the abutment 118. Intermediate its ends, the laterally projected contact arm 124 of the ground contact element is firmly supported against the rearwardly projecting end of the upstanding projection or abutment 116.

When the anchoring screw 96a is now inserted through Y bore 84a, its head will bear firmly against the contact element, holding the same in place with the shank of the ,screw passing through said element. Further, the contact element will be held against swinging movement from its assigned position due to engaging the side walls of the recess dened by shortening of the cylindrical enlargement 82a.

/hile I have illustrated and described the preferred embodiments of my invention, it is to be understood that l do not limit myself to the precise constructions herein disclosed and that various changes and modiiications may be made within the scope of the invention as defined in the appended claims.

Having thus described my invention, what I claim as new, and desire to secure by United States Letters Patent l. A multiple electric outlet device attachable to a duplex receptacle for electrically connecting a plurality of electric plugs with said receptacle, said receptacle having a plurality of pairs of prong-receiving slots, said dean electrically insulative casing having a plurality of pairs of openings adapted to receive the rprongs of said electric plugs, and a contact assembly in the casing including a plurality of rectangular contact plates formed with prong extending from one edge of the plates f orengagement in said slots, said plates being Athreaded recess, said outlet 4inserted plugs, said plates extending transversely of the casing and being spaced longitudinally of the casing with the plates of each pair being spaced apart a distance such that the prongs of an inserted plug will be in direct contact with the respective plates of each pair of plates, each of said plates having a plurality of spring tongues struck out or" the material thereof, along three peripheral side edges thereof, said tongues being adapted to be resiliently biased away from the adjacent portions of their associated plates by the prongs of inserted plugs.

2. A multiple electric outlet device attachable to a duplex receptacle for electrically connecting a plurality of electric plugs with said receptacle, said receptacle having a plurality of pairs of prong-receiving slots, said device comprising: an electrically insulative casing having a plurality of pairs of openings adapted to receive the prongs of said electric plugs, and a contact assembly in the casing including a plurality of rectangular contact plates formed with prongs extending from one edge of the plates for engagement in said slots, said plates being arranged lwithin the casing for contact by the prongs of inserted plugs, said plates extending transversely of the casing and being spaced longitudinally of the casing with the plates of each pair being spaced apart a distance such that the prongs of an inserted plug will be in direct Contact with the respective plates of each pair of plates, each of said plates having a plurality of spring tongues struck out of the material thereof, along three peripheral side edges thereof, said tongues being adapted to be resiliently biased away from the adjacent portions of their associated plates by the prongs of inserted plugs, the casing being of rectangular configuration, said openings of the casing being formed in the opposite side walls and in the back wall of the casing, each of said plates having its periphery in engagement with said side and back walls adjacent an opening of each of said walls, for engagement of each plate by corresponding prongs of a plurality of inserted plugs, the tongues of each plate extending substantially normally to an adjacent edge of the plate and terminating substantially at said adjacentedge.

3. A multiple electric outlet device attachable to a duplex receptacle for electrically connecting a plurality of electric plugs with said receptacle, said receptacle having a plurality of pairs of prong-receiving slots and a central device, comprising: an electrically insulative casing having a plurality of pairs of openings adapted to receive the prongs of said electric plugs, and a contact assembly in the casing including a plurality of contact plates formed with prongs extending from one edge of the plates for engagement in said slots,

said plates being larranged within the casing for contact by the prongs of inserted plugs, said casing being formed p connecting screws being ladapted for iixedly connecting between the several ly of the casing,

each other, said casing furcentrally disposed anchoring to front through the the sections of the casing to ther including an elongated, screw adapted to extend from back casing from back to front and to engage in the threaded recess centrally provided in the receptacle, thus to cooperate with the several contact plate prongs in xedly engaging the outlet device with said receptacle, said casing sections including means providing abutments intervening plates to space the plates longitudinalsaid plates being of rectangular configuration, and including struck-out tongues for engaging the prongs of an inserted plug, there being tongues formed on three peripheral side edges of each of the plates with each tongue of a plate extending to its respective edge of the plate.

4. A multiple electric outlet device attachable to a duplex receptacle for electrically connecting a plurality Y, of electric plugs with said receptacle, said receptacle having a plurality of pairs of prong-receiving slots, said outlet device comprising: an electrically insulative casing having a plurality of pairs of openings adapted to receive the prongs of said electric plugs, and a Contact assembly in the casing including a plurality of contact plates formed with prongs extending from one edge of the plates for engagement in said slots, said plates being arranged within the casing for contact by the prongs of inserted plugs, said casing being formed with complementary casing sections connectable to one another in plate-enclosing relation, the casing including connecting screws at the several corners thereof, said connecting screws being adapted for iixedly connecting the sections of the casing to each other, said casing further including a centrally disposed anchoring screw adapted to extend through the respective casing sections with the head of the screw disposed interiorly of the casing, said contact assembly including a ground contact element disposed wholly internally of the casing in engagement with the head of said screw and extending clear of the respective contact plates, aid ground contact element being disposed for engagement by the grounding prong of an inserted triple plug having in addition spaced contact prongs engageable with said plates.

5. A multiple electric outlet device attachable to a duplex receptacle for electrically connecting a plurality of electric plugs with said receptacle, said receptacle having a plurality of pairs of prong-receiving slots, said outlet device comprising: an electrically insulative casing having a plurality of pairs of openings adapted to receive the prongs of said electric plugs, and a contact Aassembly in the casing including a plurality of contact plates formed with prongs extending from one edge of the plates for engagement in said slots, said plates being arranged within the casing for contact by the prongs of inserted plugs, said casing being formed with complementary casing sections connectable to one another in plate-enclosing relation, the casing including connecting screws at the several corners thereof, said connecting screws being adapted for xedly connecting the sections of the casing to each other, said casing further including a centrally disposed anchoring screw adapted to extend through the respective casing sections with the head of the screw disposed interiorly of the casing, said contact assembly including a ground contact element disposed wholly internally of the casing in engagement with the head of said screw and extending clear of the respective contact plates, said ground contact element being disposed for engagement by the grounding prong of an inserted triple plug having in addition spaced contact prongs engageable with said plates, at least one of said plates being partially cut away to provide clearance for the ground contact element, said ground contact element extending at one end transversely of said one contact plate and having a free end adapted for engagement by said grounding prong and disposed between said one contact plate and an adjacent contact plate.

References Cited in the tile of this patent 

